Mike Davis just finished one up, and knowing him, it's likely very well executed and thought out. Not to mention, since it is Mike, he likely has 3-43 more in the works . I'm sure he'll be a guy to watch in the single bevel world. Then there's Butch and Randy who have the means and skills, not to mention the motivation to pull a proper one off.
I'm not saying these guys will be cheap, or have one for you yet, but you asked which Western makers are doing single bevels, and the three I mentioned all have.
By the way, I'm in the same boat, and always on the lookout for a good cheap single bevel. However, I'm hoping Mike allows me to be his guinea pig. Unfortunately, all I can catch in the winter is muskie or pickerel. Haha.